Field
The invention relates to a polyaxial bone anchoring device for coupling a bone anchoring element to a rod. The polyaxial bone anchoring device includes a receiving part, a bone anchoring element with a head and a shank, and a rod. The receiving part has a channel for receiving the rod and an accommodation space for pivotably holding the head of the bone anchoring element. The head can be locked at an angle relative to the receiving part by applying pressure onto the head via a pressure member, where the pressure member includes a deformable portion. The deformable portion can be deformed by the rod so that the head is firmly clamped or locked in the receiving part. The bone anchoring element of the polyaxial bone anchoring device can be held or maintained at a particular angular position by only using the rod, for example, without using an additional locking member.
Description of Related Art
US 2013/0345761 A1 describes a polyaxial bone anchoring device including a bone anchoring element with a shank and a head wherein the head is pivotably coupled to a receiving part which has a channel for receiving a rod. A pressure member is arranged in a receiving part and configured to exert pressure onto the head to lock the head in the receiving part. The pressure member has a deformable portion. Load applied to the pressure member by a locking member clamps the head and thereafter the locking member contacts the pressure member such that the deformable portion is deformed and the locking member comes into contact with the rod and clamps the rod.